excel - count time

[hcl]

I want to record lengths of time spent on phone calls in excel & have a total in hours & minutes, but it keeps insisting on using date format.

I enter the time in the format 10:30 for 10 minutes & 30 seconds. If I custom format the values as [mm]ss for minutes & seconds, it changes them into a time of day. It turns my example into 10:30am

[pctek]

Doesn't for me.
I checked what it used and its on Custom, hh:mm:ss. Try formatting it like that.

[kahawai chaser]

Could get a bit tricky if difference fall across two different days, so a tweak is required which is shown here

[hcl]

Doesn't for me.
I checked what it used and its on Custom, hh:mm:ss. Try formatting it like that.

still sees it as date and time, but it works as long as the total doesn't get to 24 hours or more.